libtask/context.c at master · jamwt/libtask · GitHub

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/* Copyright (c) 2005-2006 Russ Cox, MIT; see COPYRIGHT */

#include"taskimpl.h"

#if defined(__APPLE__)
#if defined(__i386__)
#defineNEEDX86MAKECONTEXT
#defineNEEDSWAPCONTEXT
#elif defined(__x86_64__)
#defineNEEDAMD64MAKECONTEXT
#defineNEEDSWAPCONTEXT
#else
#defineNEEDPOWERMAKECONTEXT
#defineNEEDSWAPCONTEXT
#endif
#endif

#if defined(__FreeBSD__) && defined(__i386__) &&__FreeBSD__<5
#defineNEEDX86MAKECONTEXT
#defineNEEDSWAPCONTEXT
#endif

#if defined(__OpenBSD__) && defined(__i386__)
#defineNEEDX86MAKECONTEXT
#defineNEEDSWAPCONTEXT
#endif

#if defined(__linux__) && defined(__arm__)
#defineNEEDSWAPCONTEXT
#defineNEEDARMMAKECONTEXT
#endif

#if defined(__linux__) && defined(__mips__)
#defineNEEDSWAPCONTEXT
#defineNEEDMIPSMAKECONTEXT
#endif

#ifdefNEEDPOWERMAKECONTEXT
void
makecontext(ucontext_t*ucp, void (*func)(void), intargc, ...)
{
ulong*sp, *tos;
va_listarg;

tos= (ulong*)ucp->uc_stack.ss_sp+ucp->uc_stack.ss_size/sizeof(ulong);
sp=tos-16;
ucp->mc.pc= (long)func;
ucp->mc.sp= (long)sp;
va_start(arg, argc);
ucp->mc.r3=va_arg(arg, long);
va_end(arg);
}
#endif

#ifdefNEEDX86MAKECONTEXT
void
makecontext(ucontext_t*ucp, void (*func)(void), intargc, ...)
{
int*sp;

sp= (int*)ucp->uc_stack.ss_sp+ucp->uc_stack.ss_size/4;
sp-=argc;
sp= (void*)((uintptr_t)sp- (uintptr_t)sp%16);	/* 16-align for OS X */
memmove(sp, &argc+1, argc*sizeof(int));

*--sp=0; /* return address */
ucp->uc_mcontext.mc_eip= (long)func;
ucp->uc_mcontext.mc_esp= (int)sp;
}
#endif

#ifdefNEEDAMD64MAKECONTEXT
void
makecontext(ucontext_t*ucp, void (*func)(void), intargc, ...)
{
long*sp;
va_listva;

memset(&ucp->uc_mcontext, 0, sizeofucp->uc_mcontext);
if(argc!=2)
*(int*)0=0;
va_start(va, argc);
ucp->uc_mcontext.mc_rdi=va_arg(va, int);
ucp->uc_mcontext.mc_rsi=va_arg(va, int);
va_end(va);
sp= (long*)ucp->uc_stack.ss_sp+ucp->uc_stack.ss_size/sizeof(long);
sp-=argc;
sp= (void*)((uintptr_t)sp- (uintptr_t)sp%16);	/* 16-align for OS X */
*--sp=0;	/* return address */
ucp->uc_mcontext.mc_rip= (long)func;
ucp->uc_mcontext.mc_rsp= (long)sp;
}
#endif

#ifdefNEEDARMMAKECONTEXT
void
makecontext(ucontext_t*uc, void (*fn)(void), intargc, ...)
{
inti, *sp;
va_listarg;

sp= (int*)uc->uc_stack.ss_sp+uc->uc_stack.ss_size/4;
va_start(arg, argc);
for(i=0; i<4&&i<argc; i++)
uc->uc_mcontext.gregs[i] =va_arg(arg, uint);
va_end(arg);
uc->uc_mcontext.gregs[13] = (uint)sp;
uc->uc_mcontext.gregs[14] = (uint)fn;
}
#endif

#ifdefNEEDMIPSMAKECONTEXT
void
makecontext(ucontext_t*uc, void (*fn)(void), intargc, ...)
{
inti, *sp;
va_listarg;

va_start(arg, argc);
sp= (int*)uc->uc_stack.ss_sp+uc->uc_stack.ss_size/4;
for(i=0; i<4&&i<argc; i++)
uc->uc_mcontext.mc_regs[i+4] =va_arg(arg, int);
va_end(arg);
uc->uc_mcontext.mc_regs[29] = (int)sp;
uc->uc_mcontext.mc_regs[31] = (int)fn;
}
#endif

#ifdefNEEDSWAPCONTEXT
int
swapcontext(ucontext_t*oucp, constucontext_t*ucp)
{
if(getcontext(oucp) ==0)
setcontext(ucp);
return0;
}
#endif